564 research outputs found

    Magnetic properties of a spin-1 Triangular Ising system

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    We studied some magnetic behaviors of Blume-Capel (BC) model in a site diluted triangular lattice by means of the effective-field theory (EFT) with correlations. The effects of the exchange interaction (J), crystal field (D), concentration (p) and temperature (T) on the magnetic properties of spin-1 BC model in a triangular lattice such as magnetization, susceptibility, phase diagram and hysteresis behaviors are investigated, in detail. The phase diagrams of the system are presented in two different planes. The tricritical point as well as tetracritical and critical end special points are found as depending on the physical parameters of the system. Moreover, when the hysteresis behaviors of the system are examined, the single and double hysteresis loop are observed for various values of the physical parameters. We show that the hysteresis loops have different coercive field points in which the susceptibility make peak at these points

    Domain Wall Depinning in Random Media by AC Fields

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    The viscous motion of an interface driven by an ac external field of frequency omega_0 in a random medium is considered here for the first time. The velocity exhibits a smeared depinning transition showing a double hysteresis which is absent in the adiabatic case omega_0 --> 0. Using scaling arguments and an approximate renormalization group calculation we explain the main characteristics of the hysteresis loop. In the low frequency limit these can be expressed in terms of the depinning threshold and the critical exponents of the adiabatic case.Comment: 4 pages, 3 figure

    Comparison of chemotherapy and hematopoietic stem cell transplantation pre and postterm DMFT scores: A preliminary study

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    Aims: Chemotherapy is frequently used as a conditioning regimen to destroy malignant marrow cells before transplantation. Xerostomia, dysphagia, altered taste perception, mucositis, soft‑tissue ulceration, and infection are common adverse oral effects of chemotherapy. The study was aimed to compare decayed, missing, filled teeth (DMFT) scores before and after hematopoietic stem cell transplantation (HSCT) and chemotherapy.Materials and Methods: Thirty‑six patients undergoing HSCT were included in the study. Apre‑HSCT dental treatment protocol was implemented that consisted of restoration of all active carious lesions, treatment of periodontal infections, and extraction of all teeth with advanced periodontal disease. Upon completion of dental treatment, the importance of rigorous and effective oral hygiene was reemphasized, and patients were recalled 6 months later. DMFT scores were calculated prior to the initiation of HSCT treatment and 6 months after transplantation.Statistical Analysis Used: Regression analysis was used to evaluate the effects of HSCT and chemotherapy on DMFT scores.Results: Wilcoxon T test showed a statistically significant difference in DMFT scores before and after HSCT (P < 0.001). Conclusions: DMFT scores were found to increase after chemotherapy and HSCT, suggesting that the risk of infection is higher among HSCT patients when compared to other individuals. The results emphasize the need for dental examinations as an integral part of examination and treatment planning for patients undergoing HSCT and chemotherapy.Key words: Chemotherapy, decayed missing filled teeth scores, hematopoietic stem cell transplantatio

    Melting of Flux Lines in an Alternating Parallel Current

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    We use a Langevin equation to examine the dynamics and fluctuations of a flux line (FL) in the presence of an {\it alternating longitudinal current} J(ω)J_{\parallel}(\omega). The magnus and dissipative forces are equated to those resulting from line tension, confinement in a harmonic cage by neighboring FLs, parallel current, and noise. The resulting mean-square FL fluctuations are calculated {\it exactly}, and a Lindemann criterion is then used to obtain a nonequilibrium `phase diagram' as a function of the magnitude and frequency of J(ω)J_{\parallel}(\omega). For zero frequency, the melting temperature of the mixed phase (a lattice, or the putative "Bose" or "Bragg Glass") vanishes at a limiting current. However, for any finite frequency, there is a non-zero melting temperature.Comment: 5 pages, 1 figur

    Gigantic peripheral osteoma of the mandible: a case report

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    Osteomas are osteogenic lesions that have a limited growth potential. They are comprised of histologically and radiographically normal bone. Osteomas are categorized as central, peripheral or extraskeletal according to location. Clinically, peripheral osteomas (PO) are unilateral, sessile or pedunculated and have mushroom-like lesions ranging from 10 to 40 mm in diameter. Osteomas affecting the mandible are rare. In this report, we presented a gigantic peripheral mass on the left mandible in a 55-year old patient exhibiting clinical signs related to neoplasia

    Facet Formation in the Negative Quenched Kardar-Parisi-Zhang Equation

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    The quenched Kardar-Parisi-Zhang (QKPZ) equation with negative non-linear term shows a first order pinning-depinning (PD) transition as the driving force FF is varied. We study the substrate-tilt dependence of the dynamic transition properties in 1+1 dimensions. At the PD transition, the pinned surfaces form a facet with a characteristic slope scs_c as long as the substrate-tilt mm is less than scs_c. When m<scm<s_c, the transition is discontinuous and the critical value of the driving force Fc(m)F_c(m) is independent of mm, while the transition is continuous and Fc(m)F_c(m) increases with mm when m>scm>s_c. We explain these features from a pinning mechanism involving a localized pinning center and the self-organized facet formation.Comment: 4 pages, source TeX file and 7 PS figures are tarred and compressed via uufile

    Phase ordering and roughening on growing films

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    We study the interplay between surface roughening and phase separation during the growth of binary films. Already in 1+1 dimension, we find a variety of different scaling behaviors depending on how the two phenomena are coupled. In the most interesting case, related to the advection of a passive scalar in a velocity field, nontrivial scaling exponents are obtained in simulations.Comment: 4 pages latex, 6 figure

    Shear bands in granular flow through a mixing length model

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    We discuss the advantages and results of using a mixing-length, compressible model to account for shear banding behaviour in granular flow. We formulate a general approach based on two function of the solid fraction to be determined. Studying the vertical chute flow, we show that shear band thickness is always independent from flowrate in the quasistatic limit, for Coulomb wall boundary conditions. The effect of bin width is addressed using the functions developed by Pouliquen and coworkers, predicting a linear dependence of shear band thickness by channel width, while literature reports contrasting data. We also discuss the influence of wall roughness on shear bands. Through a Coulomb wall friction criterion we show that our model correctly predicts the effect of increasing wall roughness on the thickness of shear bands. Then a simple mixing-length approach to steady granular flows can be useful and representative of a number of original features of granular flow.Comment: submitted to EP

    Passive Sliders on Growing Surfaces and (anti-)Advection in Burger's Flows

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    We study the fluctuations of particles sliding on a stochastically growing surface. This problem can be mapped to motion of passive scalars in a randomly stirred Burger's flow. Renormalization group studies, simulations, and scaling arguments in one dimension, suggest a rich set of phenomena: If particles slide with the avalanche of growth sites (advection with the fluid), they tend to cluster and follow the surface dynamics. However, for particles sliding against the avalanche (anti-advection), we find slower diffusion dynamics, and density fluctuations with no simple relation to the underlying fluid, possibly with continuously varying exponents.Comment: 4 pages revtex

    Heating of magnetic fluid systems driven by circularly polarized magnetic field

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    Cataloged from PDF version of article.A theory is presented to calculate the heat dissipation of a magnetic suspension, a ferrofluid, driven by7 circularly polarized magnetic field. Theory is tested by in vitro experiments and it is shown that, regardless of the character of the relaxation process, linearly and circularly polarized magnetic field excitations, having the same root-mean-square magnitude, are equivalent in terms of heating efficiency. (C) 2010 Elsevier B.V. All rights reserved
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